[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 150607
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT OCT 15 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM
THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON
SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND
METEOROLOGICAL ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0345 UTC.

...SPECIAL FEATURE...

A SURFACE 1005 MB LOW PRESSURE CENTER IS OFF THE SOUTHEASTERN
COAST OF JAMAICA. ITS POSITION HAS BEEN JUMPING AROUND THE
ISLAND OF JAMAICA SINCE 14/1200 UTC...WHEN IT STARTED OUT IN
THE NORTHWESTERN COASTAL WATERS...THEN MOVED TO NORTH CENTRAL
COASTAL JAMAICA...AND NOW TO ITS 15/0000 UTC POSITION. NUMEROUS
STRONG SHOWERS AND THUNDERSTORMS HAVE DEVELOPED IN THE WATERS
BETWEEN JAMAICA AND HAITI...AND ALL AROUND THE LOW CENTER IN
THE SOUTHEASTERN WATERS OFF JAMAICA. A SURFACE TROUGH
REMAINS FROM SOUTHEASTERN CUBA...THROUGH THE 1005 MB LOW
CENTER...TO EASTERN COASTAL NICARAGUA...AND THROUGH NICARAGUA
TO EASTERN EL SALVADOR. THE ATMOSPHERIC ENVIRONMENT...MORE
ORGANIZED CONVECTIVE ACTIVITY AND UPPER LEVEL WIND CONDITIONS...
GRADUALLY IS BECOMING BETTER ORGANIZED AND MORE FAVORABLE FOR
THE FORMATION OF A TROPICAL DEPRESSION ON SATURDAY. THIS SYSTEM
IS FORECAST TO MOVE SLOWLY WEST OR WEST-NORTHWESTWARD...AND
RESIDENTS IN JAMAICA...CUBA...AND THE NORTH CENTRAL AND
NORTHWESTERN CARIBBEAN SEA SHOULD MONITOR CLOSELY THE PROGRESS
OF THIS DEVELOPING SYSTEM. LOCALLY HEAVY RAINFALL ALSO WILL BE
POSSIBLE ACROSS JAMAICA...EXTREME SOUTHEASTERN CUBA...AND HAITI.
AN AIR FORCE RESERVE UNIT RECONNAISSANCE AIRCRAFT TENTATIVELY IS
SCHEDULED TO INVESTIGATE THE SYSTEM ON SATURDAY IF NECESSARY.

...TROPICAL WAVES...

TROPICAL WAVE ALONG 36W SOUTH OF 20N MOVING WEST 15 KT. SCATTERED
MODERATE TO ISOLATED STRONG SHOWERS AND THUNDERSTORMS FROM 10N
TO 14N BETWEEN 30W AND 35W. ISOLATED MODERATE SHOWERS AND
POSSIBLE THUNDERSTORMS ELSEWHERE FROM 10N TO 20N BETWEEN 30W
AND 40W. UPPER LEVEL WINDS ARE SHEARING CLOUD TOPS IN THE AREA
FROM 12N TO 18N BETWEEN AFRICA AND 32W.

TROPICAL WAVE ALONG 59W/60W SOUTH OF 19N MOVING WEST 10 TO
15 KT. THIS WAVE IS MOVING THROUGH THE AREA OF CYCLONIC FLOW
AROUND THE 17N58W LOW CENTER WHICH IS ABOUT 20060 NM EAST-
NORTHEAST OF GUADELOUPE. ISOLATED MODERATE SHOWERS AND LOCALLY
STRONG THUNDERSTORMS ARE FOUND FROM 10N TO 17N BETWEEN 55W
AND 60W.

...ITCZ...

ITCZ 8N13W 6N20W 10N29W 15N34W...10N37W 9N44W 11N49W. SCATTERED
STRONG SHOWERS AND THUNDERSTORMS FROM 6N TO 7N BETWEEN 38W AND
42W. ISOLATED MODERATE SHOWERS TO LOCALLY STRONG THUNDERSTORMS
ARE FOUND FROM 4N TO 11N EAST OF 30W.

...DISCUSSION...

THE GULF OF MEXICO...
THE MIDDLE TO UPPER LEVEL HIGH CENTER IN THE SOUTHEASTERN GULF
12 HOURS AGO HAS SHIFTED A BIT NOW TO BE IN THE SOUTH CENTRAL
GULF WATERS. MIDDLE TO UPPER LEVEL DRY AIR ACCOMPANIES THIS HIGH
CENTER. A DISSIPATING COLD FRONT EXTENDS FROM THE SOUTHEASTERN
FLORIDA COASTAL LOW CENTER TO SOUTH FLORIDA AND TO WESTERN CUBA.
A FEW SHOWERS ALONG THAT BOUNDARY ALREADY TO APPEAR TO HAVE
DISSIPATED. THE EASTERN FLORIDA COASTAL LOW CENTER FROM 12 HOURS
AGO HAS MOVED SOUTHWARD...NOW NEAR 26.7N 79.5W. IT DOES NOT HAVE
THE SAME BEAUTIFUL APPEARANCE IN INFRARED IMAGERY THAT IT HAD IN
VISIBLE IMAGERY. SURFACE ANTICYCLONIC FLOW AND ADVANCING HIGH
PRESSURE COVER THE GULF WATERS.

THE EASTERN CARIBBEAN SEA AND THE ATLANTIC OCEAN SOUTH OF 25N
BETWEEN 50W AND 63W...
A MIDDLE TO UPPER LEVEL TROUGH IS DIGGING AND HAS BEEN DIGGING
INTO THE EASTERN AND SOUTHEASTERN CARIBBEAN SEA...FROM A MIDDLE
TO UPPER LEVEL LOW CENTER WHICH NOW IS ABOUT 360 NM EAST OF
GUADELOUPE. THE TROPICAL WAVE ALONG 57W/58W SOUTH OF 19N IS
MOVING THROUGH THE AREA OF MIDDLE TO UPPER LEVEL CYCLONIC FLOW
WITH THIS TROUGH. ISOLATED MODERATE SHOWERS AND LOCALLY STRONG
THUNDERSTORMS ARE FOUND FROM 9N TO 16N BETWEEN 53W AND 60W...
AND IN THE CARIBBEAN SEA FROM 10N TO 14N BETWEEN 63W AND 66W.
CYCLONIC FLOW WITH THIS TROUGH COVERS THE CARIBBEAN SEA TO AT
LEAST 65W/66W.

THE WESTERN ATLANTIC OCEAN WEST OF 63W AND NORTH OF 25N
BETWEEN 50W AND 63W...
A MIDDLE TO UPPER LEVEL TROUGH/SHEAR AXIS CONNECTS ONE LOW
CENTER NEAR 36N62W TO A SECOND LOW CENTER ABOUT 280 NM NORTHEAST
OF THE SOUTHERN BAHAMAS NEAR 25N69W. THIS 25N69W CENTER IS
COMPARATIVELY MUCH LESS WELL-DEFINED THAN IT WAS 12 HOURS AGO.
MIDDLE TO UPPER LEVEL DRY AIR IS WEST OF THIS TROUGH. THE
SURFACE SCENARIO IS FULL OF LOW CENTERS AND TROUGHS AND FRONTAL
BOUNDARIES. ONE SUCH FRONTAL BOUNDARY PASSES THROUGH 30N63W TO
27N70W TO THE EASTERN FLORIDA COASTAL LOW CENTER. A DISSIPATING
COLD FRONT EXTENDS FROM THIS LOW CENTER TO SOUTH FLORIDA AND
WESTERN CUBA. BROKEN TO OVERCAST LOW AND MIDDLE LEVEL CLOUDS ARE
NORTH OF THIS FRONT. A TROUGH RUNS FROM A 1007 MB LOW CENTER
NEAR 31N60W TO 24N64W TO NORTHWESTERN COASTAL DOMINICAN
REPUBLIC. UPPER LEVEL ANTICYCLONIC FLOW AND ISOLATED MODERATE
SHOWERS WITHIN 30 TO 60 NM ON EITHER SIDE OF 28N60W
23N63W 22N68W. SCATTERED MODERATE TO STRONG SHOWERS AND
THUNDERSTORMS ARE IN BETWEEN THE 36N62W 25N69W TROUGH AND THE
CYCLONIC FLOW AROUND THE 17N58W LOW CENTER EAST OF GUADELOUPE.

THE REST OF THE ATLANTIC OCEAN...EAST OF 50W...
A DEEP LAYER TROUGH IS DIGGING INTO THE AREA FROM NORTH OF 30N.
THE TROUGH IS SUPPORTING A COLD FRONT WHICH PASSES THROUGH
32N23W TO 28N34W...AND THEN IS STATIONARY FROM 28N34W TO 32N51W.
AND NORTHWESTWARD BEYOND 30N51W. A 200 TO 300 NM WIDE BAND OF
MULTILAYERED CLOUDS AND POSSIBLE SHOWERS AND THUNDERSTORMS MARKS
THIS FRONT. AN ALREADY-EXISTING SURFACE TROUGH STRETCHES FROM
32N22W TO 27N27W TO A SURFACE 1016 MB LOW PRESSURE CENTER NEAR
24N41W. THE TROUGH CONTINUES TO 20N50W. THE CLOUDS FROM THE FRONT
APPEAR TO BE COVERING THE CLOUDINESS FROM THE TROUGH.

$$
MT


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